I. Field of the Invention
This invention relates generally to row crop cultivating equipment used in agriculture, and more specifically to a row crop cultivator which is more effective in its operation than known prior art apparatus intended for the same purpose.
II. Discussion of the Prior Art
The present invention is deemed to be an improvement over the inter-row crop cultivator described in U.S. Pat. No. 4,560,011 and 4,461,355, each of Which is assigned to the assignee of the present invention. In that prior art design, a plurality of ganged cultivator units are fixedly attached along the length of a tool bar which is arranged to be attached by a three-point hitch to a tractor-type vehicle, the tool bar extending transversely to the direction of travel of the tractor. Each of the ganged cultivating units includes a frame which is supported on a single gauge wheel which is vertically adjustable so as to effectively control depth at which other implements supported on the frame are made to penetrate the earth. These other implements typically include a coulter cutting wheel which is disposed directly behind the gauge wheel. It is intended to cut through weeds and other residue residing on the surface of the ground when minimum tillage agricultural practices are being employed. Another implement, the sweep, is disposed directly behind the coulter cutting wheel and is attached to the frame by a downwardly depending, relatively wide shank. The sweep loosens the soil and removes weeds from the row middle.
The frame of the earlier machine also supports additional implements, namely, a pair of cut-away disks which are spaced laterally outward from the gauge wheel and to either side of the path of travel of the coulter cutting wheel. The cut-away disks are designed to cut through the soil and residue at a location away from the crop row and till the area which is not affected by the sweep shares
While the prior art row cultivator described in the afore referenced patents constitutes a marked improvement over the prior art existing at the time of its market introduction, further developments within the Hiniker Company (applicant's assignee) have resulted in significant improvements over the earlier design, which improvements result in superior performance. In the prior art design, where the stabilizing coulter cutting wheel is disposed in longitudinal alignment with the gauge wheel and is displaced a considerable distance behind it, there has been a tendency for the stabilizing coulter to merely push weeds, residue and debris into the soil rather than cutting through it. This is a condition referred to as "hair-pinning"because of the U-shape of the trash after it has been run over by the coulter. In that the residue is not properly cut, it tends to buildup around the sweep shank and plugs the underside of the cultivator. It is found that cut-away discs can compound this problem by diverting residue ahead of the stabilizing coulter.
In the earlier prior art design, the downwardly depending shank to which the sweep is secured is relatively thick and the angle of attack of the sweep is low, typically only about 20.degree. to the horizontal. It has been found that as that row crop cultivator was pulled over the field, the sweeps would turn over the trash laden soil as slabs of earth, especially when working heavier and/or wetter soils. These slabs would then peel off the sweep and be displaced sufficiently to the side so that they would land on the crop row and crush or damage the young growing plants. While this problem could be obviated by operating the tractor at a reduced speed, the resulting waste of time, especially on larger farms, may well become excessive The addition of shields to cure the slabbing problem has proven only moderately successful because such shields tend to compound the plugging problem already mentioned.
Another drawback of the earlier prior art design reflected in the aforereferenced patents is related to the overall length of the cultivator unit, i.e., the distance that it projects rearward of the tool bar. This produces a torque on the tool bar which requires more powerful hydraulic components to lift the gang and reduces tractor handling dynamics.